The present invention relates to a thermal barrier liner for containers, and more particularly, to a thermal barrier liner placed in contact with the inner surface of the container and a method of installing the liner by mechanically inserting the liner in the container.
Portable beverage containers are used to hold many types of beverages to include carbonated soft drinks, fruit drinks, and beer. It is well known to provide a protective internal liner for those containers made of metal such as aluminum or steel to help preserve the beverage within the container by preventing undesirable chemical reactions that would otherwise take place over time by direct contact of the beverage with the metallic container. For containers made of plastic, there is typically no internal liner provided because the plastic material is inherently non-reactive with respect to most types of beverages.
Many beverages are preferably consumed at relatively cold temperatures, for example, between about 36° F. and 50° F. For carbonated soft drinks and beer, consumers typically prefer these beverages to be chilled prior to consumption. Traditional chilling or cooling techniques include placing the containers in a chilled environment such as a refrigerator or cooler, and then serving the beverage once the beverage has reached a desired chilled temperature.
When the beverage is removed from the chilled environment, the beverage begins to quickly warm due to a combination of external heat sources including ambient heat of the surrounding environment, contact with warm surfaces such as the consumer's hand or the surface on which the container is placed, as well as radiant heat from the sun or other light sources. Heat transfer takes place through the walls, base, and top of the container to the beverage. Without some means provided for insulating the container, the beverage so quickly warms that, in many circumstances, it becomes undesirable or unfit for consumption.
There are a number of inventions that have been developed for purposes of insulating a beverage within the container such that it is maintained at a desired temperature prior to and during consumption. For example, it is well known to provide external thermal barriers, such as an insulating sleeve that is applied over the exterior sidewall of the container. It is also known to provide an insulated label on the sidewall of the container. There are a number of disadvantages to these traditional methods of insulating beverages. An insulating label/sleeve only covers the container sidewall, therefore leaving the bottom of the container exposed. For insulated labels, they are typically much thicker than a non-insulated label and, therefore, standard packaging line may have to be substantially modified to accommodate these special labels. For insulating sleeves, these require the consumer to maintain a separate component to maintain the beverage at a desired cold temperature.
Some efforts have been made to provide an internal insulating liner for containers. One example is disclosed in U.S. Pat. No. 6,474,498. This reference discloses a thermally insulated container for canned beverages including a lining formed from a plastics material. The preferred embodiments suggest using a plastic closed cell material to include closed cell material similar to bubble wrap. The liner is intended to be placed into the container as by a slidable fit within the container so as to be in contact with the cylindrical inner surface of the container wall. The lining member may include an adherent surface allowing the lining to adhere to the internal wall of the container. In an alternative embodiment, this reference discloses a closed cell material that can be provided as a layer on the interior surface of the metal container in addition to or in place of a conventional lacquered coating applied to the interior surface of the container.
U.S. Patent Application Publication No. 2006-0073298 discloses a multi-layer inner liner provided for a container and an extrusion method for a beverage container. The method contemplates blow molding the inner liner by co-extrusion of a first inner layer of a thermoplastics material and a second inner layer made of a foam material having insulating properties. The inner layer of foam is further disclosed as having micro-spheres that expand during the blow-molding process.
U.S. Patent Application Publication No. 2006-0054622 discloses an insulated beverage container having an inner liner that adheres to the inside of the container. The inner liner is made from a crystalline ceramic material.
While the foregoing references may be adequate for their intended purpose, there is still a need for an internal thermal barrier to maintain a beverage at a desired temperature wherein the thermal barrier can be incorporated within a liner installed by using standard packaging machinery.
It is one object of the invention to provide a thermally insulated beverage container that can effectively and safely keep beverages at a desired temperature during consumption of the beverage.
It is yet another object of the present invention to provide a thermally insulated beverage container by providing a thermal barrier liner utilizing a single material that exhibits specific common desirable properties resulting in creation of an insulated thermal barrier.
It is yet another object of the present invention to provide a unique combination of materials that, when combined, exhibit desirable thermal barrier properties.
It is yet another object of the present invention to provide a method of installing a thermal barrier, such as a mechanically inserted thermal barrier liner having the form of a sheet-like substrate.
It is yet another object of the present invention to provide a thermal barrier that can be used in different types of beverage containers, such as those made from metal or made from plastic.
It is yet another object of the present invention to provide a thermally insulated beverage container that can be introduced into existing beverage manufacturing, distribution, and sales sectors without requiring significant alterations in manufacturing machinery or processes.
In accordance with the present invention, a thermally insulated beverage container is provided having a thermal barrier liner positioned in contact with inner surface of the container. The container of the present invention may include any known beverage container, such as those made from aluminum or steel that holds beverages such as beer or carbonated soft drinks. The container of the present invention may further include known plastic containers, such as PET bottles or cans.
In a first embodiment of the present invention, the thermal barrier liner may include use of a single material having a cell structure comprising a plurality of voids or pockets and wherein the liner covers the interior surface of the container to include the container sidewall and base of the container. In this embodiment, the liner may also be referred to as a closed cell substrate layer or foam layer. The material used for the barrier liner in this embodiment has a stretchable or elastic capability such that the voids may increase in physical size without rupturing. The particular liner material and manner of installing the liner can be selected such that the cell sizes create a thermal barrier liner of a desired thickness when the container is opened. The thickness of the barrier liner as well as the composition of the barrier liner in terms of the amount of void spaces within the liner can also be adjusted to optimize the thermal barrier liner for purposes of insulating the beverage. The thermal barrier liner may be made from a cavitated or extruded monolayer film substrate containing gas permeable closed cells. The thermal barrier liner could also be made by combining different materials. For example, two rolls of formed material can be laminated them together through the use of adhesives or heat and pressure. One or both materials could incorporate cell structures and when combined, the materials form an integral thermal barrier liner. Further, the thermal barrier liner could be made in a co-extrusion process or a post extruded process. In a co-extrusion process, the materials could be combined by heat and pressure as extrudate is generated from an extruding device, or the materials can be laminated to one another with some assistance from heat and pressure but also from an applied adhesive. In other embodiments of the present invention, the thermal barrier liner includes a base material containing encapsulated gases or phase change materials. The encapsulated gases or phase change materials are dispersed throughout the base layer. In these embodiments, the base material can be made from a laminated, extruded, or coated film structure.
In another embodiment of the present invention, the thermal barrier liner includes a combination of materials that, when combined, exhibit thermal barrier properties. This embodiment may be referred to as a composite liner including a combination of: (i) a cell structure comprising a plurality of voids or pockets; (ii) microencapsulated gases; and/or (iii) microencapsulated phase change materials. In this embodiment, the base material can also be made from a laminated, extruded, or coated film structure including a desired dispersion of gas permeable closed cells.
In another embodiment of the present invention, an interior liner is provided that is offset or spaced from the interior surface of the wall of the container. This liner has one end secured to either the top or bottom/dome of the container and is sealed to the top or bottom to prevent gas and liquid flow through the area of connection. The other end of the liner remains unattached and is spaced from the top or bottom of the container depending on which end of the liner is attached. When the container is filled and prior to consumption, a small amount of gas is trapped in this annular gap along with liquid that fills the container. When the container is opened for consumption, the container is tipped so that the beverage can be poured from the container.
If the liner is secured to the top of the container, the unattached lower end is spaced from the bottom of the container. When the container is tipped to a sufficient angle, the unattached lower end of the liner is not submerged in the beverage therefore exposing a portion of the annular gap to the air. When the container is returned to its upright position after the user has poured an amount of the beverage, the unattached end is re-submerged in the beverage thereby trapping air in the annular gap. The trapped air results in the creation of a thermal barrier to keep the beverage cool.
If the liner is secured to the bottom of the container, the unattached upper end is spaced from the top of the container and when the container is tipped to a sufficient angle, the beverage will be poured from the annular gap thus evacuating an amount of liquid in the annular gap and the liquid being replaced by air since the gap is exposed to the air. The liner then acts as a dam to prevent liquid from migrating back into the annular gap.
In either way in which the liner is installed in the container, an increased volume of gas in the annular gap results in the creation of an air barrier that serves as an effective thermal barrier to keep the beverage at the desired temperature for consumption.
In yet another embodiment, the liner can be made from a mesh material wherein the material has a pattern of voids or gaps. When the container is opened, the gas bubbles from nucleation will cling to the mesh creating a concentration of gas bubbles on the material. The concentrated gas bubbles form an effective thermal barrier to prevent heat transfer to the beverage within the container. The mesh may have voids or gap sizes that allow the beverage to easily pass through the liner, or the mesh material may have very small voids that somewhat restrict the flow of the beverage through the liner. The void sizes can be selected to optimize the ability of the bubbles to attach to the liner. Other ways in which to maximize the concentration of bubbles on the liner is to provide a surface treatment/modification wherein the mesh material has surface properties that encourage the formation and retention of bubbles thereon. For example and as discussed below in reference to the preferred embodiments, the surface of the liner could be irregular or textured which greatly assist in the retention of bubbles on the surface of the liner.
In order to increase the amount of gas that is able to fill the annular gap for the embodiment in which the unattached end is at the lower end of the container or in order to maximize the gas bubbles that attach to the mesh liner, the liner may incorporate a material that enhances nucleation of the gas in the beverage. Another option available for increasing the amount of gas to fill the annular gap or to create a bubble layer on the liner is to place a conventional widget in the container. A widget is used in some malt beverage containers to increase the rate of de-gassing of the beverage thus creating a more robust head when the beverage is served. A widget used in the present invention creates a greater number of bubbles that can attach to the liner.
In yet another embodiment of the present invention, a thermal barrier liner may be provided in the form of a multi-layer coating construction wherein voids or gas pockets are found between the layers thereby providing an effective thermal barrier. In this embodiment, a co-extrusion lamination process can produce the multi-layer coating where portions of adjacent layers are sealed to one another while other portions are not sealed thus creating the gas pockets or void areas between the layers.
In yet another aspect of the present invention, a method is provided for installing the thermal barrier liner to the interior surface of a beverage container. The liner is preferably in sheet form, but incorporating the various insulating features.
The thermal barrier liner is preferably pre-made and stored in a continuous roll of material. The roll is unwound near the area in the manufacturing process where the liner is to be mechanically installed into the beverage container. The roll of barrier material is cut into predetermined sized pieces and placed within respective containers such that the liner material maintains contact with the interior sidewall of the containers.
The thermal barrier liner in the first embodiment of the present invention is gas permeable thus having the ability to equilibrate with ambient pressure conditions. More specifically, during the application of the liner to the container, the voids or pockets formed in the liner will contain gas of the surrounding environment, and the ambient pressure will determine the void sizes. After the container has been filled and sealed, the interior of the container develops a higher pressure in which the void areas further fill with gas contained in the container, such as carbon dioxide or nitrogen. This gas resides in the headspace and the gas can also be found dissolved in the beverage if the beverage is carbonated. Since the container is under pressure, the voids may decrease in size as compared to the size of the voids under ambient pressure conditions; however, the voids will contain a greater amount of gas due to the higher pressure conditions in which equilibrium is reached and pressure across the liner is equal. The voids fill with the gas (es) over a relatively short period of time due to the gas permeable nature of the liner material.
Once the container is opened, the thermal barrier liner transitions to equilibrium with ambient pressure wherein the pressurized gas contained within the voids causes an immediate expansion of the size of the voids. The increased size of the voids creates a thickened liner that is an effective thermal barrier liner to maintain beverage at a desired temperature.
Other features and advantages of the present invention will become apparent from a review of the following detailed description, taken in conjunction with a review of the drawings.
With reference to the drawings,
In accordance with a first embodiment of the present invention, a thermal barrier liner 30 is provided as shown in
The arrangement and size of the voids/gaps 36 may be a result of either how the liner 30 is manufactured and/or may be determined during a curing process wherein the voids/gaps form over a period of time. For example during manufacture of the liner, the liner can be oven dried to evaporate any solvents or other compounds used. Curing can also be conducted to condition the state of the microencapsulated gas, liquid, or solid materials used in order to place them in the best state prior to filling and sealing the container. The void areas may be randomly dispersed and randomly sized. However, depending upon the material used as the liner, a more orderly cellular pattern may result. The percentage of void or open cell space volume can range between about 10 to about 95 percent of the overall volume of the thermal barrier liner.
One important attribute of the substrate 32 is that it be gas permeable such that when placed under pressure, the substrate will equilibrate resulting in a substantially uniform distribution of gas within the voids 36. Furthermore, when pressure is reduced, the substrate should have the capability to expand such that the cell walls 34 do not burst, tear, or otherwise degrade and, rather, will maintain an inflated state for a period of time thus creating an effective thermal barrier liner realized by the increased volume of the substrate 32.
It has been found through testing that some existing container liner materials have the capability to be formed into foamed substrates and are elastic such that the substrate maintains integrity among various pressure ranges. However, in order to optimize the closed cell substrate configuration and necessary gas permeability, foaming agents can be added to the liner materials. The liner materials can include polymeric or synthetic formulations of thermoplastics. Two acceptable liner materials may include expanded styrene and polyethylene foam. These liner materials may be used to form a thermal barrier liner having a gas permeable closed cell substrate configuration that is able to equilibrate at working pressure changes.
Referring to
The thermal barrier liner is preferably of a thickness under ambient pressure conditions such that it does not unduly displace the typical amount of the beverage within the container. Thus when the barrier liner expands under ambient pressure conditions, the beverage in the container will not be forced through the opening in the container.
Referring to
An added benefit with respect to first embodiment is that when the container is being chilled (when unopened) fast chilling of the beverage may take place since the thermal barrier liner is in its more compressed or thin state, thereby allowing rapid heat transfer away from the container without having to overcome a relatively thickened insulating member.
The permeability of the thermal barrier liner is such that gas is allowed to permeate through the cell walls over a period when under pressure to reach equilibrium, for example, a few hours, but the cell walls are not so permeable that immediate deflation takes place when ambient pressure is reduced. Therefore, the thermal barrier liner will maintain a full thickness for at least a period of time in which a consumer would normally consume the beverage. It is contemplated that it may take up to twenty-four hours for pressurized gas within the container when the container is sealed to permeate through the thermal barrier liner but when the container is opened, it will take at least one hour before the thermal barrier liner reaches equilibrium with the reduced pressure of the environment. Thus, a full, thickened barrier liner is maintained during the time period in which a consumer normally consumes the beverage.
One example of an additive component that may be used as a microencapsulated gas includes Expancel®. Expancel® is a commercially available product that includes elastic micro-spheres or microcapsules, roughly ten micrometers in diameter, filled with a small amount of liquid hydrocarbon gas. When heated within a known temperature range, the liquid hydrocarbon gas expands within the micro-spheres causing the micro-spheres to expand to a diameter of nearly four times the size of the liquid state, to approximately forty micrometers. As temperature increases, the gas continues to expand and, thus, the micro-spheres continue to expand in size. The micro-spheres can be used either in an unexpanded liquid state or a pre-expanded gaseous state, depending on application capabilities and the elasticity of the base material 42. With respect to use as an insulation material in the present invention, use of pre-expanded spheres 40 would create a pattern of voids in the base layer.
As mentioned, the microcapsules create voids in the base layer and thereby enhance the thermal barrier capability of the liner. The size and distribution of the voids created by the gas or liquid filled spheres can be selected to provide the desired level of insulation for the container. A greater concentration of micro spheres will produce more voids. The particular gas or liquid selected can be selected to optimize the desired level of insulation.
It is also contemplated that liquid filled micro spheres can be provided so that the liquid changes phase to a gaseous state when the beverage warms during consumption by the consumer. Thus, when the beverage is maintained in its cooled state during storage, the micro-spheres would remain in a liquid state. Referring to
For both the first and second embodiments, one acceptable base liner material 42 may include expanded styrene or polyethylene foam. During manufacturing of the liner, increased curing times may be required depending upon the addition of an additive component which may, therefore, increase the curing time.
Now referring to
This multi-layer liner can be constructed of multiple layers of the same material, or may be made of dissimilar materials. With respect to a single material used, if the single material is layered and sealed in a complex pattern, or applied at different times with different temperatures or viscosities, voids or gas pockets may be formed between layers. With respect to use of dissimilar materials, void areas between the layers may be formed more as a function of the ability of layers to adhere to one another, among other factors.
Unlike conventional liners applied to the interior of containers, it is the intent in the embodiment shown in
Referring to
The bulk roll 80 may be dispensed from a shaft 82 driven by a dispensing device 84. The roll of liner material may be dispensed so that a predetermined length of the material is placed in alignment with a cutting device 86 having a cutting blade 88 that cuts discrete lengths of pieces of the liner material. One cut piece of material 83 is shown adjacent the cutting blade. Referring to
After the liner has been installed, the top of the container is secured to the sidewall, the container is filled with the beverage, and finally the container is sealed and pressurized.
The thermal barrier liner of the present invention is installed such that it does not degrade or otherwise damage the conventional protective interior liner of the container that is used to prevent contact between the beverage and the metallic sidewall and base. Thus, while the thermal barrier liner makes intimate contact with the conventional interior liner, the thermal barrier liner is not abrasive and otherwise does not produce an adverse affect on the conventional interior liner.
With respect to a preferred thickness of the thermal barrier liner, it shall be understood that none of the embodiments are strictly limited to a specific range but it has been found that a liner between about 1.0 mm to 3.0 mm provides adequate insulation without displacing a quantity of the beverage that adversely affects desired headspace within the container. For the first embodiment, the thermal barrier liner can be between about 0.5 mm and 1.5 mm in thickness when the container is sealed and pressurized, and the thermal barrier liner expands to between about 1.0 mm and 3.0 mm mm when the container is opened and exposed to the environment.
It shall be understood that the thermal barrier liner of the present invention significantly departs from traditional liners used to coat the interior of a container for purposes of preventing spoilage of the beverage in the container. More specifically, conventional liners are formed to create a very smooth, thin, and non-insulating layer. The thermal barrier liner of the present invention by provision of a closed cell substrate, and/or with microencapsulated materials, or a multi-layer liner provides a unique solution for a thermal barrier, and may optionally be made from similar materials as the conventional interior liner.
As also mentioned above, provision of a gas permeable liner that can equilibrate between different ambient pressures allows creation of a thicker insulated layer once the container is opened. Providing this active or size changing barrier liner also has the benefit of allowing the container to be more easily cooled when unopened, yet allows substantially the same amount of beverage to be maintained in the container since the barrier liner occupies a minimum volume when under pressure or when chilled.
With respect to the embodiment of the present invention providing a multi-layered liner, the structure here is intended to provide voids between layers as opposed to conventional liners where the intent is to minimize void areas between the layers in order to maximize the bond between the layers. In fact, many can liners require additives therefore improving the wetting or contact area to maximize bonding between the layers. However, with the present invention, the bonding areas between the layers is reduced to the point where a balance can be achieved between a bond strength such that the layers maintain integrity and remain bound to one another, yet gaps or void areas are formed to allow permeation of gas and subsequent expansion thereby creating an effective thermal barrier liner. Some techniques to promote rough and irregular surface bonding between the layers may include use of high viscosity materials, cold application temperatures, patterned sealing and use of different materials between layers that are not fully miscible.
While the preferred embodiments of the present invention have been shown specifically with respect to a traditional aluminum or steel container, it shall be understood that the thermal barrier liners of the present invention can be incorporated within any type of container to include plastic containers such as PET bottles, or conventional aluminum or steel cans used to contain fruits, vegetables, soups, meat or other products.
Referring to
Referring to
The distance between the unattached end 96 of the liner and the base of the container can be adjusted to provide an optimal angle at which air is allowed to enter the annular gap for purposes of creating an enhanced thermal barrier.
The embodiment of
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A number of different materials can be used for the liner since the liner itself does not have to have insulating properties. Examples of acceptable liner materials include polyethylene, polyethylene terephthalate (PET), polypropylene, foil, or laminated foil. Alternatively, the liner material could have its own inherent insulating properties in order to further enhance the thermal barrier characteristics of the container. In such a case, the liner could be made from the materials as discussed above with respect to the other embodiments of the present invention shown in
In order to keep the liner correctly aligned within the container to maintain a uniformly spaced annular gap, the liner can be stiffened by thermo-formed features in the material. For example if PET is used as the liner material, small beads or bumps/protrusions can be thermo-formed in the material. If a foil material is used, small protrusions can be formed by embossing.
Referring to
Trapped air in a beverage container is problematic and quality standards for most beverages require that only very small amounts of oxygen are permitted. One solution for evacuating air that may be trapped in the annular gap when the container is filled is to alter the filling nozzle so that the beverage is first directed into the annular gap thereby evacuating the gap from air and then filling the remainder of the container. Use of a purge gas such as Nitrogen can also be used to evacuate trapped air in the container. The purge gas can also be directed into the annular gap to evacuate trapped air in the annular gap, as well as directing purge gas in the head space of the container.
Although the liner of
For the embodiments of
In each of the embodiments of
Another way in which to increase nucleation would be to incorporate a widget in the container. One example of a known widget used to create a more robust head on a malt beverage includes the use of a small plastic nitrogen filled sphere having a very small hole formed on the sphere. The sphere is typically added to the container before the container is sealed and the sphere floats with the hole just below the surface of the beverage. Before the container is sealed, a small shot of liquid nitrogen is added to the beverage. Pressure increases in the container as the liquid nitrogen evaporates, and the beverage is slowly forced into the sphere thereby compressing the nitrogen gas in the sphere. When the container is opened, the compressed gas in the sphere quickly forces the beverage through the hole causing agitation of the beverage which nucleates the gas in the beverage creating bubbles. The widget could be formed in a ring shape and placed in the annular gap. The widget would therefore provide a way of directing the bubbles 102 in the annular gap.
Referring to
While the present invention has been discussed for use in keeping beverages cool, it shall also be understood that the present invention can also be used to thermally insulate a beverage intended to be served at room temperature or warmer. For the first embodiment of the present invention incorporating the closed cell substrate that is capable of thermally insulating a container by only changes in pressure, this embodiment can certainly be used for those beverages that are intended to be served at room temperature or warmer.
The automatic activation of the thermal barrier liner under variable pressure or temperature conditions makes the thermal barrier liner ideal in those commercial applications where the beverages may be stored under pressure, such as the case for carbonated soft drinks and beer.
Because the thermal barrier liner of the present invention may be installed by mechanically inserting the liner in an unfinished container, it is unnecessary to significantly alter or otherwise modify known beverage packaging machinery or processes.
While the present invention has been described with respect to various preferred embodiments, it shall be understood that various other changes and modifications to the invention may be made, commensurate with the scope of the claims appended hereto.
Priority is claimed from U.S. Provisional Patent Application No. 60/980,135 filed on Oct. 15, 2007, entitled “INSERTED THERMAL BARRIER LINER FOR CONTAINERS”, which is incorporated herein in its entirety by this reference.
Number | Date | Country | |
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60980135 | Oct 2007 | US |